Copper electrolytic solution containing amine compound having specific skeleton and organosulfur compound as additives, and electrolytic copper foil produced using the same

ABSTRACT

The invention has an object of obtaining a low-profile electrolytic copper foil made by electrolytic copper foil manufacturing using a cathode drum such that the surface roughness on the rough surface side (the opposite side to the lustrous surface) is low. In particular, the invention has an object of obtaining an electrolytic copper foil that can be finely patterned and have an excellent elongation and tensile strength at normal and high temperatures. This object is attained by using a copper electrolytic solution containing, as additives, an organosulfur compound, and an amine compound having a specific skeleton represented by undermentioned general formula (1) obtained by additively reacting an amine compound and a compound having one or more epoxy groups in a molecule thereof to an addition reaction.                  
 
(In general formula (1), R1 and R2 are each selected from a group consisting of hydroxyalkyl groups, ether groups, aromatic groups, aromatic-substituted alkyl groups, unsaturated hydrocarbon groups, and alkyl groups, A represents an epoxy compound residue, and n represents an integer greater than or equal to 1.)

TECHNICAL FIELD

The present invention relates to a copper electrolytic solution used inthe manufacture of an electrolytic copper foil, and in particular to acopper electrolytic solution used in the manufacture of an electrolyticcopper foil that can be finely patterned and has an excellent elongationand tensile strength at normal and high temperatures.

BACKGROUND ART

In general, to manufacture an electrolytic copper foil, a rotating metalcathode drum having a polished surface and an insoluble metal anode thatgoes around the periphery of approximately the lower half of the cathodedrum are used, and a copper electrolytic solution is made to flowbetween the cathode drum and the anode. A potential is also appliedbetween the cathode drum and the anode, whereby copper iselectrodeposited onto the cathode drum. Once the electrodeposited copperhas reached a prescribed thickness, the electrodeposited copper ispeeled off from the cathode drum, whereby copper foil is manufacturedcontinuously.

Copper foil obtained in this way is generally referred to as raw foil.This raw foil is subsequently subjected to various surface treatment andis then used in printed wiring boards or the like.

A conventional copper foil manufacturing apparatus is shownschematically in FIG. 1. In this electrolytic copper foil apparatus, acathode drum is installed in an electrolysis bath housing anelectrolytic solution. The cathode drum 1 rotates in a state partiallysubmerged (i.e. with approximately the lower half submerged) in theelectrolytic solution.

An insoluble anode 2 is provided so as to go around the lower half ofthe outer periphery of the cathode drum 1. There is a constant gap 3between the cathode drum 1 and the anode 2, and the electrolyticsolution flows through this gap. In the apparatus of FIG. 1, two anodeplates are used.

In FIG. 1, the constitution is such that the electrolytic solution isfed in from below, passes through the gap 3 between the cathode drum 1and the anode 2, and flows over upper edges of the anode 2, thuscirculating. A prescribed voltage is maintained between the cathode drum1 and the anode 2 using a rectifier.

As the cathode drum 1 rotates, the copper electrodeposited from theelectrolytic solution grows thicker, and once the copper has become atleast a certain thickness, the raw foil 4 is peeled off, and is wound upcontinuously. The thickness of the raw foil manufactured in this way isadjusted through the distance between the cathode drum 1 and the anode2, the flow rate of the electrolytic solution fed in, and the amount ofelectricity fed in.

With copper foil manufactured using such an electrolytic copper foilmanufacturing apparatus, the surface contacting the cathode drum becomesa specular surface, but the surface on the other side becomes a roughsurface having irregularities. With ordinary electrolysis, theirregularities on the rough surface are severe, and hence there is aproblem that undercutting is prone to occurring during etching, and thusfine patterning is difficult.

However, recently, as the density on printed wiring boards has beenincreased, the circuit width has been reduced and the number of layershas been increased, and accompanying this copper foil that can be finelypatterned has come to be required. To carry out fine patterning, copperfoil having crystal grains of a uniform size and having a uniformetching rate and a uniform solubility, i.e. copper foil having excellentetching properties, is required.

Moreover, regarding properties required of copper foil for printedwiring boards, not only elongation at normal temperatures, but alsoelongation at high temperatures are required to prevent cracking due tothermal stress. Furthermore, high tensile strength for dimensionalstability of printed wiring boards are required. However, copper foilfor which irregularities on the rough surface are severe as above causesa problem of not being suited to fine patterning at all as describedabove. Studies have thus proceeded into making the rough surface have alow profile.

It is known that, in general, a low profile can be achieved by adding alarge amount of animal glue or thiourea to the electrolytic solution.However, such additives have a problem of causing the elongationpercentage to drop dramatically at normal and high temperatures, thuscausing a great deterioration in the properties as a copper foil forprinted wiring boards.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to obtain a low-profileelectrolytic copper foil by electrolytic copper foil manufacturing usinga cathode drum such that the surface roughness on the rough surface side(the opposite side to the lustrous surface) is low. In particular, it isan object to obtain an electrolytic copper foil that can be finelypatterned and has excellent elongation and tensile strength at normaland high temperatures.

The present inventors found that by adding optimum additives to anelectrolytic solution, low profile foil can be formed.

Therefore, it is possible to obtain an electrolytic copper foil that canbe finely patterned and has excellent elongation and tensile strength atnormal and high temperatures.

Based on this finding, the present inventors discovered that, byelectrolysis using a copper electrolytic solution containing an aminecompound having a specific skeleton and an organosulfur compound, it ispossible to obtain an electrolytic copper foil that can be finelypatterned and has an excellent elongation and tensile strength at normaland high temperatures. In the case of an electrolytic copper foilmanufacturing method in which a copper electrolytic solution is made toflow between a cathode drum and an anode, copper is electrodepositedonto the cathode drum, and the electrodeposited copper is peeled offfrom the cathode drum to continuously manufacture copper foil. Thepresent invention was thus achieved.

Specifically, the present invention is constituted as follows.

(1) A copper electrolytic solution containing, as additives, anorganosulfur compound and an amine compound having a specific skeletonrepresented by undermentioned general formula (1) obtained by additivelyreacting an amine compound and a compound having one or more epoxygroups in a molecule thereof.

(In general formula (1), R1 and R2 are each selected from a groupconsisting of hydroxyalkyl groups, ether groups, aromatic groups,aromatic substituted alkyl groups, unsaturated hydrocarbon groups, andalkyl groups, A represents an epoxy compound residue, and n representsan integer greater than or equal to 1.)

(2) A copper electrolytic solution according to (1) above, wherein theepoxy compound residue A of said amine compound having a specificskeleton has a linear ether linkage.

(3) A copper electrolytic solution according to (1) or (2) above,wherein said amine compound having a specific skeleton includes any ofundermentioned general formulae (2) to (9).

(n: an integer from 1 to 5)

(n: an integer from 1 to 3)(In general formulae (2) to (9), R₁ and R₂ are each selected from agroup consisting of hydroxyalkyl groups, ether groups, aromatic groups,aromatic-substituted alkyl groups, unsaturated hydrocarbon groups, andalkyl groups.)

(4) A copper electrolytic solution according to (1) above, wherein saidorganosulfur compound is a compound represented by undermentionedgeneral formula (10) or (11).X—R¹—(S)_(n)—R²—YO₃Z¹  (10)R⁴—S—R³—SO₃Z²  (11)(In general formulae (10) and (11), R¹, R² and R³ are each an alkylenegroup having 1 to 8 carbon atoms, R⁴ is selected from a group consistingof hydrogen,

, X is selected from a group consisting of hydrogen, a sulfonic acidgroup, a phosphonic acid group, and sulfonic acid or phosphonic acidalkali metal salt groups or ammonium salt groups, Y is sulfur orphosphorus, Z¹ and Z² are each hydrogen, sodium or potassium, and n is 2or 3.)

(5) An electrolytic copper foil produced using the copper electrolyticsolution according to any of (1) through (4) above.

(6) A copper-clad laminate using the electrolytic copper foil accordingto (5) above.

In the present invention, it is important for the electrolytic solutionto contain an organosulfur compound, and the amine compound having thespecific skeleton represented by above-mentioned general formula (1)that is obtained through an addition reaction between an amine compoundand a compound having one or more epoxy groups in a molecule thereof. Ifonly one of these were to be added, then it would not be possible toattain the object of the present invention.

The amine compound (1) having the specific skeleton is synthesizedthrough the addition reaction represented by the undermentioned reactionformula. Specifically, the amine compound having the specific skeletoncan be produced by mixing together an amine compound and a compoundhaving one or more epoxy groups in a molecule thereof, and reacting forapproximately 30 minutes to 6 hours at 50 to 150° C.

(In the above formula, R₁ and R₂ are each selected from the setconsisting of hydroxyalkyl groups, ether groups, aromatic groups,aromatic-substituted alkyl groups, unsaturated hydrocarbon groups, andalkyl groups, A represents an epoxy residue, and n represents an integergreater than or equal to 1.)

Specific examples of R₁ and R₂ in the structure of the amine compoundhaving the specific skeleton are a hydroxyethyl group and ahydroxyisopropyl group (‘hydroxyalkyl groups’ above), a 2-ethoxyethylgroup and a 2-propoxyethyl group (‘ether groups’ above), a phenyl groupand a naphthyl group (‘aromatic groups’ above), a tolyl group, a xylylgroup, a cumenyl group and a 1-phenylethyl group (‘aromatic-substitutedalkyl groups’ above), an allyl group, a 1-propenyl group, an isopropenylgroup, a 1-butenyl group, a 2-butenyl group and a 2-methylallyl group(‘unsaturated hydrocarbon groups’ above), and a methyl group, an ethylgroup, a propyl group, a butyl group, a pentyl group, a hexyl group, aheptyl group and an octyl group (‘alkyl groups’ above). From theviewpoint of water-solubility, substituents having too large a number ofcarbon atoms are not desirable, with it being preferable for the numberof carbon atoms per one substituent to be not more than 8.

It is preferable for the amine compound having the specific skeleton tobe a compound having a linear ether linkage in the epoxy compoundresidue A. Compounds having the structural formulae of undermentionedgeneral formulae (2) to (9) are preferable as such compounds in whichthe epoxy compound residue A has a linear ether linkage, with the epoxycompound residue A in each of general formulae (2) to (9) being as shownbelow.

(n: an integer from 1 to 5)

(n: an integer from 1 to 22)

(n: an integer from 1 to 3)(In general formulae (2) to (9), R₁ and R₂ are each selected from agroup consisting of hydroxyalkyl groups, ether groups, aromatic groups,aromatic-substituted alkyl groups, unsaturated hydrocarbon groups, andalkyl groups.)

Moreover, the organosulfur compound is preferably a compound having astructural formula of above-mentioned general formula (10) or (11).

Examples of organosulfur compounds represented by above-mentionedgeneral formula (10) are as follows, with it being preferable to usethese.HO₃P—(CH₂)₃—S—S—(CH₂)₃—PO₃HHO₃S—(CH₂)₄—S—S—(CH₂)₄—SO₃HNaO₃S—(CH₂)₃—S—S—(CH₂)₃—SO₃NaHO₃S—(CH₂)₂—S—S—(CH₂)₂—SO₃HCH₃—S—S—CH₂—SO₃HNaO₃S—(CH₂)₃—S—S—S—(CH₂)₃—SO₃Na(CH₃)₂CH—S—S—(CH₂)₂—SO₃H

Moreover, examples of organosulfur compounds represented byabove-mentioned general formula (11) are as follows, with it beingpreferable to use these.HS—CH₂CH₂CH₂—SO₃Na

HS—CH₂CH₂—SO₃Na

The weight ratio of the amine compound to the organosulfur compound inthe copper electrolytic solution is preferably in a range of 1:5 to 5:1,more preferably 1:2 to 2:1. The concentration of the amine compound inthe copper electrolytic solution is preferably in a range of 1 to 50ppm.

In addition to the amine compound having the specific skeleton and theorganosulfur compound described above, publicly known additives, forexample polyether compounds such as polyethylene glycol andpolypropylene glycol, and, polyethyleneimine, phenazine dyes, animalglue and cellulose may be added into the copper electrolytic solution.

Moreover, a copper-clad laminate obtained by laminating on theelectrolytic copper foil of the present invention has an excellentelongation and tensile strength at normal and high temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing an example of an electrolytic copper foilmanufacturing apparatus.

FIG. 2 is the FT-IR spectrum of a dimethylamine compound obtained in anexample of synthesis of the amine compound having the specific skeleton.

FIG. 3 is the H-NMR spectrum of the dimethylamine compound obtained inthe example of synthesis of the amine compound having the specificskeleton.

FIG. 4 is the ¹³C-NMR spectrum of the dimethylamine compound obtained inthe example of synthesis of the amine compound having the specificskeleton.

BEST MODE FOR CARRYING OUT THE INVENTION

Following is a more detailed description of the present invention,showing examples.

EXAMPLE OF SYNTHESIS OF THE AMINE COMPOUND HAVING THE SPECIFIC SKELETON

10.0 g of the epoxy compound represented by the undermentioned chemicalformula (Denacol EX-521 made by Nagase Kasei Kogyo K.K.) (0.0544 mol ofepoxy groups) and 10.7 g (0.0544 mol) of dibenzylamine were put into a3-mouth flask, and using a condenser tube with dry ice-methanol as acoolant, the reaction was carried out at 60° C. for 3 hours, thusobtaining an epoxy resin modified with dibenzylamine.

Similarly, epoxy resins modified with each of bis(2-ethoxyethyl)amine,diethanolamine, diphenylamine, diallylamine and dimethylamine wereobtained. The FT-IR, ¹H-NMR and ¹³C-NMR spectra of the epoxy resinmodified with dimethylamine are shown in FIGS. 2 to 4. The compoundobtained was the dimethylamine compound represented by theundermentioned chemical formula.

Examples 1 to 12 and Comparative Examples 1 to 9

35 μm electrolytic copper foil was manufactured using an electrolyticcopper foil manufacturing apparatus as shown in FIG. 1. The compositionof the electrolytic solution was as follows, with the amounts added ofthe additives being as shown in Table 1.

Cu: 90 g/l H₂SO₄: 80 g/l Cl: 60 ppm Temperature: 55 to 57° C. AdditiveA: Disodium bis(3-sulfopropyl)disulfide (CPS, made by Raschig Inc.)Additive B: Sodium 3-mercapto-1-propanesulfonate (MPS, made by RaschigInc.) Additive C: The amine compound having the specific skeletonobtained in the example of synthesis described above C1:Dibenzylamine-modified substance C2: Bis(2-ethoxyethyl)amine-modifiedsubstance C3: Diethanolamine-modified substance C4:Diphenylamine-modified substance C5: Diallylamine-modified substance C6:Dimethylamine-modified substance

The surface roughness Rz (μm) of each electrolytic copper foil obtainedwas measured in accordance with JIS B 0601, and the normal-temperatureelongation (%), the normal-temperature tensile strength (kgf/mm²), thehigh-temperature elongation (%) and the high-temperature tensilestrength (kgf/mm²) were measured in accordance with IPC-TM650. Theresults are shown in Table 1.

TABLE 1 Addi- Addi- tive tive Additive C Tensile Tensile A B (ppm) RzElongation*1 strength*1 Elongation*2 strength*2 (ppm) (ppm) C1 C2 C3 C4C5 C6 (μm) (%) (kgf/mm²) (%) (kgf/mm²) Example 1 50 0 50 0 0 0 0 0 1.028.10 32.2 13.9 21.7 Example 2 50 0 0 50 0 0 0 0 1.00 6.62 30.5 16.2 21.0Example 3 50 0 0 0 50 0 0 0 0.90 8.71 31.0 18.2 20.6 Example 4 50 0 0 00 50 0 0 1.13 8.90 37.9 12.6 20.7 Example 5 50 0 0 0 0 0 50 0 1.15 7.1234.2 12.1 20.1 Example 6 50 00 0 0 0 0 0 50 0.97 6.75 31.5 16.9 21.1Example 7 0 50 50 0 0 0 0 0 1.10 8.23 32.9 14.2 20.8 Example 8 0 50 0 500 0 0 0 1.02 6.69 31.2 17.0 22.3 Example 9 0 50 0 0 50 0 0 0 0.92 8.9033.0 17.3 22.2 Example 10 0 50 0 0 0 50 0 0 1.16 8.70 36.6 12.3 21.0Example 11 0 50 0 0 0 0 50 0 1.20 7.23 34.9 12.4 20.3 Example 12 0 50 00 0 0 0 50 0.98 6.83 31.9 16.5 21.4 Comparative 0 0 0 0 0 0 0 0 5.8 8.9037.9 12.6 20.7 Example 1 Comparative 100 0 0 0 0 0 0 0 5.3 0.2 10.3 1.015.3 Example 2 Comparative 0 100 0 0 0 0 0 0 6.1 0.2 11.2 1.2 14.9Example 3 Comparative 0 0 100 0 0 0 0 0 5.3 0.3 10.9 1.1 16.0 Example 4Comparative 0 0 0 100 0 0 0 0 5.8 0.1 11.1 1.0 15.8 Example 5Comparative 0 0 0 0 100 0 0 0 5.3 0.2 12.3 1.3 15.3 Example 6Comparative 0 0 0 0 0 100 0 0 5.8 0.2 13.0 1.2 14.9 Example 7Comparative 0 0 0 0 0 0 100 0 5.2 0.2 12.2 1.1 15.9 Example 8Comparative 0 0 0 0 0 0 0 100 4.9 0.2 10.3 2.7 12.8 Example 9 *1 atnormal temperature *2 at high temperature

As shown in Table 1 above, for Examples 1 to 12 in which the additivesof the present invention (the amine compound having the specificskeleton and the organosulfur compound) were added, each Rz was in arange of 0.90 to 1.20 μm, each normal-temperature elongation was in arange of 6.62 to 8.90%, each normal-temperature tensile strength was ina range of 30.5 to 37.9 kgf/mm², each high-temperature elongation was ina range of 12.1 to 18.2%, and each high-temperature tensile strength wasin a range of 20.1 to 22.3 kgf/mm². In this way, even though aremarkably low profile was achieved, the normal-temperature elongation,the normal-temperature tensile strength, the high-temperature elongationand the high-temperature tensile strength all exhibited values similarto or better than those of Comparative Example 1 in which no additiveswere added. In contrast, for Comparative Example 1 in which no additiveswere added and Comparative Examples 2 to 9 in which only one of theadditives was added, a low profile was not achieved. Moreover, in thecases in which only one of the additives was added, thenormal-temperature elongation, the normal-temperature tensile strength,the high-temperature elongation and the high-temperature tensilestrength actually became worse.

INDUSTRIAL APPLICABILITY

As described above, the copper electrolytic solution of the presentinvention to which the amine compound having the specific skeleton andthe organosulfur compound have been added is extremely effective inmaking the rough surface of an electrolytic copper foil obtained have alow profile. Moreover, excellent properties are observed in thatextension properties can be maintained effectively not only at normaltemperatures but also at high temperatures, and furthermore high tensilestrength can similarly be obtained. Moreover, it is understood thataddition of both the amine compound having the specific skeleton and theorganosulfur compound is important, since only then can the aboveproperties be obtained.

1. A copper electrolytic solution containing copper to beelectrodeposited and, as additives, an organosulfur compound, and anamine compound having a specific skeleton represented by undermentionedwherein obtained by additively reacting an amine compound and thecompound having one or more epoxy groups in a molecule thereof,

wherein R₁ and R₂ are each selected from the group consisting ofhydroxyalkyl groups, ether groups, aromatic groups, aromatic-substitutedalkyl groups, unsaturated hydrocarbon groups, and alkyl groups, Arepresents an epoxy compound residue, and n represents an integergreater than or equal to
 1. 2. A copper electrolytic solution accordingto claim 1, wherein the epoxy compound residue the of said aminecompound having a specific skeleton has a linear ether linkage.
 3. Acopper electrolytic solution according to claim 1, wherein said aminecompound having the specific skeleton includes any of undermentionedwherein,

(n: an integer from 1 to 5)

, wherein n₁ is an integer from 1 to 5,

, wherein n₃ is an integer from 1 to 3 and R₁ and R₂ are each selectedfrom the group consisting of hydroxyalkyl groups, ether groups, aromaticgroups, aromatic-substituted alkyl groups, unsaturated hydrocarbongroups, and alkyl groups.
 4. A copper electrolytic solution according toclaim 1, wherein said organosulfur compound is a compound represented byundermentioned wherein,X—R¹—(S)_(n)—R²—YO₃Z¹  (10)R⁴—S—R³—SO₃Z²  (11) , wherein R¹, R² and R³ are each an alkylene grouphaving 1 to 8 carbon atoms, R⁴ is selected from a group consisting ofhydrogen,

, X is selected from the group consisting hydrogen, the sulfonic acidgroup, the phosphonic acid group, and sulfonic acid or phosphonic acidalkali metal salt groups or ammonium salt groups, Y is sulfur orphosphorus, Z¹ and Z² are each hydrogen, sodium or potassium, and n is 2or 3.